Hybrid tire cord and method for manufacturing the same

Abstract

A hybrid tire cord has more uniform physical properties, and improved strength and fatigue resistance. The hybrid tire cord can easily be manufactured. The hybrid tire cord includes a nylon primarily twisted yarn and an aramid primarily twisted yarn, wherein the nylon primarily twisted yarn and the aramid primarily twisted yarn are secondarily twisted together, and after untwisting of the secondary twisting of the hybrid tire cord having a predetermined length, a length of the aramid primarily twisted yarn is 1.005 to 1.025 times a length of the nylon primarily twisted yarn.

The invention claimed is: 
     
       1. A hybrid tire cord comprising:
 a nylon primarily twisted yarn; and 
 an aramid primarily twisted yarn, 
 wherein the nylon primarily twisted yarn and the aramid primarily twisted yarn are secondarily twisted together, 
 if the secondary twist of the hybrid tire cord with a predetermined length were untwisted, a length of the aramid primarily twisted yarn would be 1.005 to 1.025 times a length of the nylon primarily twisted yarn, 
 the aramid primarily twisted yarn has a 0.1 to 5% lower twist number than a twist number of the nylon primarily twisted yarn, and 
 the hybrid tire cord has a merge structure having a partial covering structure. 
 
     
     
       2. The hybrid tire cord according to  claim 1 , wherein the nylon primarily twisted yarn has a first twist direction,
 the aramid primarily twisted yarn has a second twist direction, 
 the nylon primarily twisted yarn and the aramid primarily twisted yarn are secondarily twisted together in a third twist direction, 
 the second twist direction is the same as the first twist direction, and 
 the third twist direction is opposite to the first twist direction. 
 
     
     
       3. The hybrid tire cord according to  claim 1 , wherein a weight ratio of the nylon primarily twisted yarn to the aramid primarily twisted yarn is 20:80 to 80:20. 
     
     
       4. The hybrid tire cord according to  claim 1 , further comprising an adhesive agent coated on the nylon primarily twisted yarn and the aramid primarily twisted yarn,
 wherein strength at break and elongation at break measured by ASTM D885 (2004) are 8.0 to 15.0 g/d and 7 to 15%, respectively, and 
 a strength maintenance percentage after disk fatigue test conducted by JIS-L 1017 (2008) of Japanese Standard Association (JSA) is 90% or higher. 
 
     
     
       5. The hybrid tire cord according to  claim 4 , wherein the hybrid tire cord has 3% LASE, 5% LASE, and 7% LASE measured by ASTM D885 (2004), of 0.8 to 2.0 g/d, 1.5 to 4.0 g/d, and 3.0 to 6.0 g/d, respectively. 
     
     
       6. The hybrid tire cord according to  claim 5 , wherein the hybrid tire cord has a shrinkage of 1.5 to 2.5%,
 wherein the shrinkage is measured under a primary load of 0.01 g/denier at 180 ° C. for 2 minutes.